Inclusive ω photoproduction from nuclei and ω in the nuclear medium
Inclusive ω photoproduction from nuclei and ω in the nuclear medium
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DOI：
10.1140/epja/i2006-10169-6
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发表时间：
2006-10
期刊：
影响因子：
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通讯作者：
E. O. Báguena;M. Kaskulov;E. Gajate
中科院分区：
文献类型：
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作者：
E. O. Báguena;M. Kaskulov;E. Gajate
为了提取关于核介质中ω质量移动的信息，我们分析了在艾尔莎获得的数据，从那里已经提出了ω质量移动的证据。我们开发了一个Monte Carlo模拟程序，该程序考虑了在ω产生区附近的（γA→ π0γX）反应以及随后的ω → π0γ衰变。对π0γ不变质量分布的计算结果与实验结果进行了比较，并得出结论：在核物质密度下，π0γ不变质量的分布与ω宽度增大到90MeV左右，质量没有变化是一致的。这种宽度的变化与从ω产生的A依赖性中的透明度比获得的初步结果是一致的。目前的结论与以前声称的ω质量移动的证据的差异源于本文讨论的背景的不同选择。
With the aim of extracting information on the shift of the ω mass in the nuclear medium we analyze data obtained at ELSA from where claims for evidence of a mass shift of the ω have been made. We develop a Monte Carlo simulation code which takes into account the possible reactions in the experimental set-up of (γA→ π0γX) in the vicinity of the ω production region with subsequent ω → π0γ decay. We compare our results with experiment for the distribution of π0γ invariant masses and conclude that the distribution is compatible with an enlarged ω width of about 90MeV at nuclear-matter density and no shift in the mass. This change in the width would be compatible with the preliminary results obtained from the transparency ratio in theA-dependence of ω production. The discrepancy of the present conclusions with former claims of an evidence for a shift of the ω mass stems from a different choice of background which is discussed in the paper.